Compound document image compression using multi-region two layer format

摘要

Two layer formatting of documents for compatibility with two layer formatting schemes while maintaining color information and edge sharpness for text. A document is divided into multiple regions based upon bodies of text having the same color. A text layer and a non-text layer are specified for each region. The text layer includes a text color along with binary values for each pixel to specify whether to use the text color or a background color. The non-text layer includes a red-green-blue value for each pixel to specify its color for both image or non-text information including the background color for the bodies of text. The text layer is compressed using a lossless compression method and the non-text layer is compressed using a lossy compression method.